A wireless local area network (WLAN) Basic Service Set (BSS) often comprises an access point and multiple stations that communicate with each other. OFDMA may allow multiple stations to communicate with the access point using the same channel, by having each communication take place on a separate sub-channel. The access point may assign multiple stations their own sub-channels to communicate on. Having multiple stations communicate on different sub-channels reduces the chance of collision.
Before stations can begin communicating with an access point for the first time, they need to establish an association with the access point that they have not associated with in the past. This can be difficult for certain stations because a station may not be able to reach the access point due to power limitations or channel and sub-channel conditions. Once associated, stations may attempt to randomly and continuously communicate with the access point. Hence, any transmission sent by the station may be vulnerable to collision with another transmission sent by another station. Furthermore, the access point may not be aware of how many new stations are trying to communicate with it. Hence, the access point may be unable to allocate an appropriate number of sub-channels for stations to use to while contending for uplink access with the access point. This may lead to unnecessary collisions between transmissions when stations try to communicate with the access point, which adds latency to the network and degrades the overall system performance.